High and low-pressure oil burner combustion heads



Dec. 10, 1957 q, M. CZARNECKI 2,81

HIGH AND LOW-PRESSURE OIL BURNER COMBUSTION HEADS Filed Aug. 24. 1953 a /4 v i 11/ I III/III 1 [1W1 I 1 1 1 7' 1 I5 I] 9 Q INVEN TOR. (AS/MEI? M. (ZARA/[C/f/ United States Patent HIGH AND. LOW-PRESSURE on. BURNER, COMBUSTION HEADS.

Casimer M. Czarnecki, Philadelphia, Pa., assignor to Eddington Metal Specialty Company, Eddington, Pa., 2 copartnership,

Application August 24, 1953, ,S,erial No. 376,103, a

1 Claim. Cl. 158-76) The present invention relates to high and low-pressure combustion heads adapted to burn liquid hydrocarbon fuels. In particular this invention relates to improvements in high and low-pressure combustion heads for oil burners.

Modern development in industrial and domes-tic heating units has seen the advent of the liquid fuel burner as a more efiicient substitute for the conventional coal furnace, kerosene stove and the like. These new burners are for the most part automatic in operation, dis,- pensing with the necessity of the constant attentionv required by their predecessors. Common amongst the various types of liquid fuel burners is the ,pressure je type burner wherein liquid fuel under pressure is prepared for burning by passing through a nozzle where it is bro.- ken down into finely divided particles in an atomized state presenting a greater surface area for a more rapid and efiicient burning. These burners are of the high pressure and low-pressure types. The atomized fuel issuing from the nozzle is mixed, with converging air currents supplied by a blower in order to attain efficient and complete combustion and to derive the maximum heat values from the fuel.

It is of great importance in burners of this, type to maintain optimum operating conditions, particularly with regard to the flow pattern of the air currents supplied by the blower to the fuel. jet issuing from the nozzle. The slightest variation in the flow pattern from the optimum will result in incomplete and ineflicient burning, excessive fuel consumption. per unit of heat produced, and a smoky flame with resultant carbon deposition. The efliciency and completeness of the combustion is determined by-an analysis of the products of combustion, the combustion efiiciency varying directly with: the quantity of carbon dioxide in the combustion products; thus, it is desirable to have a high CO content in the combustion products.

A problem has existed in the past of maintaining the proper flow pattern for the air current supplied by the blower to the fuel jet due, to interferences from the ignition electrodes and the fuel line, causing undesirable turbulence to be set-up within the burner head. Also, the surface contour of the walls of the orifice through which the air current passes has further contributed to an improper flow pattern at the fuel jet area.

Another problem which has existed in the past has been the rapid deposition of carbon on the face of the nozzle, due to a partial vacuum formed at the nozzle orifice. which tends to pull the flame back against the nozzlewith the consequent deposition of carbonthereon.. This, of course, interferes with the pattern of the jet spray and further contributes to decreasing the burni-ngefficiency.

In accordance with the present invention, means are provided for properly channeling the air current and: for peeved-ting interference of the electrodes and fuel line with the flow pattern so as to achieve optimum results 2t and maximum burning efficiency. Means are also provided for breaking the partial vacuumatthe nozzle orifice and forcing the flame awaytherefrom,'thusreducing carbon deposition to a minimum.

Itis an object of invention, therefore, to provide an improved oilburner combustion head.

It is another object of this invention to provide a lowpressure oil burner combustion head with air-guiding means for optimum mixing and burning of the fuel.

It is a furtherobjectof" this invention to provide a high-pressure oil burner combustion head with; air-guiding means for optimum mixing and burning of the fuel.

A further objectis to provide an oil burner combustion head with air-guiding means for destroying the vacuum at the nozzle orifice and reducing carbon deposition; thereon-.

These; objects, together with some of the advantages to be derived in utilizing the present invention, will become apparent from the following detailed description and fromthe accompanying drawings describing the preferred embodiment of this invention in which similar numerals-refer; to similar parts throughout the several views.

Figure 1 is a side elevational view of the low-pressure combustion head partly in section and with parts broken away showing the relative position of the guidevanes on the cylinder covering the electrode ends, and showing circumferential holes in the end of the cylinder for the introduction of secondary air currents to break the nozzle vacuum.

Figure 2 is a front elevational view of the low-pres: sure combustion head varied-cylinder for guiding the blower air currents, showing the relative position of the guide vanes and the spaces t-herebetween, looking aft.

Figure 3 is a front elevational view of the high pres sure combustion head vaned-cylinder for guiding the blower air currents showing the relative position of the guide vanes and the, overlapping of the vane ends, looking aft.

Figure 4 is a front elevational view of a m odifieaflqn of the low-pressure combustion head varied-cylinder of Figs. 1 and 2 showing the electrodes and fuel, nozzle in; stalled, and showing a small variable port in the rear wall thereof in addition to the circumferential holes in the forward end as shown in Figs. 1 and 2 for they induc: tion of secondary air currents to break the nozzle vacu- Referring to Figs. 1 and 2, a cast iron cylindrical orifice plate 10 approximately 4 /2 in. in diameter and having a 2% in, orifice 11, a flat annular surface 12 and a convex annular surface 13, is supported by a cylindrical casing 14 extending rearwardly from the, con,- vex side of the plate 10. and encasing the combustion head elements comprising the present invention. En closed within the casing 14 are a fuel nozzle 15, and electrodes 16 extending to a point adjacent theno 1e opening 17, the said nozzle opening and, electrodes lying in substantially coplanar relationship with the orifice 11. The electrodes 16 are protected bya cylindrical porcelain casing 18, while the nozzle is fed throuh; tubu; lar member 19 adjoining said nozzle. Cironmso "hing and supporting the electrodes 16 and the nozzle 1 5 with in the casing 14 is an aluminum cylinder 20, having circumferential guide vanes 21 thereabout for directing and controlling the flow of air outwardly toward the orifice 11. This cylinder is preferably 3% in. in diameter by 1% in. in length. The guide vanes21 are pref: erably positioned at an angle of about 3Q from the rearward diametric plane of the cylinder 2.0;, a shown in Fig. l, and extend forwardly to. a point approximate- 1y n. rom, t e front end of the cylinder" 20 The a cylinder 20 has been purposely made to extend beyond the forward end of the vanes 21 so as to cover the ends of the porcelain casings 18 and thus preclude their interfering with the flow pattern of the air passing forwardly through the guide vanes. The aft end of the cylinder 20 is closed-in and is provided with apertures 22 and 23 for supporting the porcelain casings 18, and aperture 24 for supporting tubular member 19, as shown in Fig. 3, while the forward end is left open. The front end of the cylinder 20 is preferably spaced 1%; in. from the orifice 11.

Withthis particular arrangement of elements in combination, air supplied to the combustion head by the con-' vventional burner blower and traveling in the direction indicated by the arrow in Fig. 1, enters the vaned-cylinder from the rearward end thereof where it is guided by the vanes 21 over the cylinder 20 and out the orifice 11. The extended cylinder prevents the porcelain casings 18 covering the electrodes 16 from interfering with the fiow pattern, While the convex surface 13 of the orifice plate directs the air-flow in a controlled converging fashion whereupon the air stream issuing therefrom mixes with the fuel-jet spray issuing from the nozzle opening 17, presenting an optimum air-fuel mixture and spray pattern at the point of ignition by the electrodes 16. As a result maximum burning efliciency is obtained, as indicated by the high CO content of the products of combustion.

To prevent the deposition of carbon on the orifice face of the fuel nozzle a plurality of /8 in. radial holes 25 may be placed about the circumferential surface of the forward portion of the vaned-cylinder in front of the vanes 21, as indicated in Fig. 1. These holes induce a flow of air downward thereinto and forward along the fuel nozzle 15 whereupon the force of this air current breaks the partial vacuum existing adjacent to the nozzle opening 17, which vacuum sucks the flame back against the nozzle 15 causing carbon deposition thereon. This induced air-flow in breaking the said vacuum forces the flame away from the nozzle 15 and thus prevents the undesirable deposition of carbon thereon. An alternate means for accomplishing the same result is indicated in Fig. 4 wherein an adjustable port 26 is provided in the back surface of the cylinder 20 to permit the flow of secondary air from the burner blower to pass therethrough breaking the vacuum in the nozzle opening 17 in substantially the same manner as described above.

The above language describes generically the essence of the present invention. There are two variations of this invention, however, particularly adapted for use in lowpressure and high-pressure oil burners respectively. These are described in detail below.

Basically, the overall combination of the elements in both the low-pressure and high-pressure combustion heads are substantially the same, the one material exception being the relative position of the guide vanes 21 about the r cylinder 20.

In the low-pressure combustion head the vanes 21 are so positioned about the periphery of the cylinder 20 that in looking rearward along the axis of said cylinder, a space of about 4 in. exists between the forward end of one vane and the aft end of the adjacent vane, as shown in Fig. 2. Such an arrangement provides a smooth flow of air past the vanes and eliminates the interference of one vane with the flow past an adjacent vane, resulting in an improved air-flow and better mixing of the air with the fuel. Also, such an arrangement of the vanes reduces the common rumbling noise heard in oil burners and reduces the amount of smoke produced on combustion. In addition to the relative position of the vanes, the forward end of each vane is cut back at one side and at the bottom 27 thereof at an angle of about 30 from the vertical edge of the vane and starting at a point approximately midway the height of the vane, as shown in Figs. 2 and 4. This feature provides, what is in effect, a bevelled corner which curves a-portion of the air-flow in 4 a forward direction in preparation for its exit past the convex surface 13 through the orifice 11.

In the high-pressure combustion head the vanes 21 are so positioned about the periphery of the cylinder 20 that in looking rearward along the axis of said cylinder the forward end of one vane overlaps the aft end of the adjacent vane in spaced relationship by approximately 1 in. as shown in Fig. 3. This is necessary so as to produce a desired interference of the air-flow past one vane with the air-flow past an adjacent vane, resulting in a high degree of turbulence within the casing 14 so as to ensure adequate mixing of the fuel and air, since in the high-pressure system only fuel is introduced into the tubular member 19 and is not pre-mixed with any air therein as in the case of the low-pressure system. Thus, all the mixing takes place ahead and external of the nozzle opening 17, requiring suflicient turbulence for proper mixing.

Although the present discussion has been limited to the above-described embodiment, other variations thereof are possible without departing from the spirit of the invention. It is therefore not intended that the invention be limited to the particular dimensions and materials disclosed in the above-described embodiment, but only to the inventive concept as defined in the appended claim.

What is claimed is;

An oil burner combustion head comprising, in combination, a cylindrical housing, an orifice plate on the forward end of said housing and having an orifice therein with an inwardly facing convex annular surface surrounding said orifice, a fuel nozzle within said housing and having an atomizing opening disposed within said convex surface, a pair of electrodes for igniting fuel emerging from said nozzle and having ends closely adjacent to said atomizing opening, porcelain insulating members encasing said electrodes, a cylindrical member within said housing and encompassing said nozzle and porcelain-encased electrodes, guide varies on said cylindrical member and spaced circumferentially thereabout, said cylindrical member having a rear end defined by a diametric plane, said guide vanes having rear ends coplanar with said rear end and disposed at an angle of thirty degrees with respect to said diametric plane and having front ends spaced rearwardly from the front end of said cylindrical member, said guide vanes cooperating withsaid convex annular surface to obtain optimum mixing of air and fuel for combustion, the forward end of said cylindrical member having a plurality of circumferentially spaced radial holes for inducing a secondary flow of air inwardly therethrough and outwardly through said orifice to prevent carbon deposit on said fuel nozzle, the rear end of said cylindrical member having an aperture and means to adjust the effective area of said aperture, said aperture inducing an additional secondary flow of air to further aid in the prevention of carbon deposit on said fuel nozzle, said guide vanes being arranged so that there is a circumferential gap between the forward end of one vane and the rear end of the next adjacent vane, the forward end of each vane being cut back at an angle of thirty degrees from the vertical edge of said vane and starting at a point midway of the height thereof and extending radially inwardly so as to provide an optimum flow pattern for combustion.

References Cited in the file of this patent UNITED STATES PATENTS 1,923,330 Sallee Aug. 22, 1933 2,066,806 Smith et a1. Jan. 5, 1937 2,078,021 Rodler Apr. 20, 1937 2,206,070 Andler July 2, 1940 2,219,696 Mueller et al Oct. 29, 1940 2,393,897 Glendenning Jan. 29, 1946 2,531,538 Smith Nov. 28, 1950 2,649,148 Tapp et a1 Aug. 18, 1953 2,676,648 Dennis et a1 Apr. 27, 1954 

